Pharmacokinetics of dextropropoxyphene and nordextropropoxyphene in elderly hospital patients after single and multiple doses of distalgesic. Preliminary analysis of results.

The plasma elimination half-life of dextropropoxyphene and its metabolite nordextropropoxyphene was investigated in seven elderly hospital patients after the administration of both single and multiple doses of Distalgesic. The mean elimination half-life of dextropropoxyphene after multiple dosing was 35.7 h (range 24.0-50.6 h) and the mean half-life of nordextropropoxyphene was 53.3 h (range 25.1-76.3 h). The half-lives of both dextropropoxyphene and nordextropropoxyphene are much longer than those reported by other investigators in younger subjects.